In daily life, a user usually needs to measure a distance or a length. For example, when purchasing furniture, a space of a house needs to be measured, and a length, a width, and a height of the furniture also need to be measured, so as to determine whether a size of the furniture matches the space of the house. To meet such measurement requirements, the user usually needs to purchase a length measurement tool such as a measuring tape, and carries the tool everywhere when needed. This brings great inconvenience. Once the user forgets to carry the tool, measurement cannot be performed, which causes a big headache. In addition, because of a limited length of such a tool, when a to-be-measured length exceeds a measuring range of the tool, multiple measurements need to be performed. This is inconvenient and leads to a relatively great error.
With rapid development and popularization of intelligent terminals such as a smart phone, a tablet computer, and a smartwatch, most users have terminals with a camera, and some of the terminals are provided with two cameras. In the prior art, a distance from a to-be-measured object to a terminal may be measured based on the two cameras; however, a size of the to-be-measured object cannot be measured.